Support DATA_VARCHAR for bound literals.

pars_bound_lit_t: Change 'address' from 'void*' to 'const void*'.

include/pars0pars.h

@@ -488,7 +488,7 @@ struct pars_user_func_struct {
 /* Bound literal. */
 struct pars_bound_lit_struct {
 	const char*	name;		/* name */
-	void*		address;	/* address */
+	const void*	address;	/* address */
 	ulint		length;		/* length of data */
 	ulint		type;		/* type, e.g. DATA_FIXBINARY */
 	ulint		prtype;		/* precise type, e.g. DATA_UNSIGNED */

pars/pars0sym.c

@@ -206,6 +206,11 @@ sym_tab_add_bound_lit(
 		*lit_type = PARS_BLOB_LIT;
 		break;
 
+	case DATA_VARCHAR:
+		len = 0;
+		*lit_type = PARS_STR_LIT;
+		break;
+
 	case DATA_INT:
 		ut_a(blit->length <= 8);
 		len = blit->length;